The invention relates to a method for installing a seat cover, including at least one shaped spar, onto a seat body that includes at least one securing element whose base is positioned over at least one slot in the seat body into which the shaped spar may be secured.
A shaped spar that is combined with a covering material is known from the European Patent EP 403 815 B1. There are slots in the seat body into which recessed securing elements are arranged. The seat cover is connected to the seat body so that the shaped spar is pressed into the securing elements from above. In this manner, simple installation of the seat cover onto a seat body that consists, for example, of foam, is possible. It has been shown however, that pressing the shaped spar into the securing elements is difficult because of the elasticity of the seat cover. An automated installation of the seat cover onto the seat body is additionally made more difficult because the shaped spar is secured to the underside of the seat cover and therefore cannot be gripped by robot grippers or the like. When pressed from above, the seat cover material becomes a hindrance so that machine gripping without damaging the material is not possible. Even manual installation has the difficulty that the position of the shaped spar and the securing element located below it must be detected by xe2x80x9cfeelxe2x80x9d.
It is therefore a principal object of the present invention to provide a method for installing a seat cover provided with at least one shaped spar that allows automated seat cover installation.
This object, as well as other objects which will become apparent from the discussion that follows, are achieved, according to the present invention, by providing a method which includes at least the following steps:
(a) penetrating the seat body with a gripper jaw of a shaped spar gripper from the seat body underside into the slot;
(b) opening the gripper jaw assembly, gripping the shaped spar, and closing the gripper jaw assembly;
(c) applying tension by means of the gripper jaw assembly gripping the shaped spar toward the underside of the seat body until the shaped spar clicks or is secured in place in the securing element; and
(d) opening the gripper jaws of the shaped spar gripper and removing the shaped spar gripper from the seat body.
This method is a reversal of the customary installation procedure. While the shaped spar is pressed into the securing element from the upper side of the seat cover in accordance with the state of the art, the method according to the invention uses the opposite approach, namely pressing the seat body from below, gripping the shaped spar, and then pressing it into the securing element until it clicks or snaps into place.
The seat body is advantageously positioned on top of a seat body bracket. Particularly for seat bodies made of soft foam, the forces necessary to create the snap connection between the shaped spar and the securing element are distributed over a greater area so that the deformation of the seat body during installation is reduced, resulting in reduced return forces within the seat body.
Penetration of the seat body may be performed by a cutting tool in soft foam and similar materials that is preferably positioned on the tip of the shaped spar gripper. A single cut can allow the insertion of the shaped spar gripper.
It is especially advantageous if at least one access channel is included in the slot that extends from the base of the slot to the underside of the seat body and through which the shaped spar gripper may be passed. This access channel may be included in the seat body as a first step, for which techniques such as drilling or grinding, or melting and cutting in the case of thermo-plastic foam materials, are particularly suited.
A seat body can also be used in which at least one access channel is included at the time of manufacture that extends from the base of the slot to the underside of the seat body, and through which the shaped spar gripper may be fed.
At least one access channel should be positioned between each pair of securing elements in order to distribute the forces evenly to the shaped spars and securing elements, and thus to ensure that the shaped spar clicks into place in all the securing elements on the seat body.
The invention further relates to a seat cover installation device used to perform the method described above. Since the installation of seat covers has always been performed manually, it is a further object of the invention to provide an installation device by means of which the method according to the invention may be performed automatically in order to secure a seat cover to a seat body.
This object is achieved by a seat cover installation device with a seat body bracket and at least one shaped spar gripper which may be dislocated by a first actuation device with respect to the seat body bracket, and which includes a gripper jaw assembly with at least two gripper jaws that may be opened or closed by means of a second actuation device.
Gripper jaws and shaped spar grippers may be operated independently of each other using drive mechanisms such as pneumatic cylinders or stepper motors. It is therefore possible to reach through the seat body from beneath, grip the shaped spar hanging down from the positioned seat cover, and insert it into the securing elements. Since the shaped spar is freely accessible from below in the slot, it may be gripped positively, centered, and secured using force.
The object is also achieved by a seat cover installation device with at least one fixed, positioned shaped spar gripper and a seat body bracket that may dislocated with respect to the shaped spar gripper via a first actuation device, whereby the shaped spar gripper includes a gripper jaw assembly with at least two gripper jaws that may be opened or closed by means of a second actuation device.
For this, the entire seat body bracket is moveable with respect to the fixed, vertically-positioned shaped spar grippers. The weight of the seat body bracket is sufficient to overcome friction forces in the support and to cause a sinking so that the first actuation device needs only to operate in one direction. Thus, for example, simpler pneumatic cylinders with no double chamber may be used as an actuation device.
This device allows penetration of the seat body by the gripper device and automatic gripping of the shaped spar without requiring additional positioning. Based on the jaw-type formation, a broad aperture is provided in an open gripper jaw assembly so that it may grip, center, and surround a shaped spar not positioned precisely above the securing elements with no extra action required by the operator.
A shaped spar gripper with the following properties is particularly advantageous:
(a) The shaped spar gripper includes a guide tube into which a tension rod coupled with the gripper jaws is inserted, and which may be at least partially drawn into the gripper jaws; and
(b) The gripper jaws are connected via their supporting shanks using a coupling whereby the tension rod is connected to at least one of the supporting shanks and/or the coupling.
The tube-shaped formation with gripper jaws that may be integrated within the guide tube permits a compact design, and consequently requires only a small width of the access channel incorporated into the seat body.
For a full understanding of the present invention, reference should now be made to the following detailed description of the preferred embodiments of the invention as illustrated in the accompanying drawings.